EX flashs and optical triggers, a possible work around:

As most people know by now the vast majority of optical triggers on the market will not repeatedly fire an EX series speed light.
Instead the flash has to be powered off, then back on again after every shot.

While surfing a local trading site I found an acution for some optical triggers that also inculded a link with a refernce on how to modiy these triggers so they work with EX speed lightes.

http://www.graphic-fusion.com/equipment.h​tm#slaves

The refernce is towards the bottom, under the picture of the optical triggers.
They seem be a farily common and cheap type, and while the fix isn't very describtive, hopefully its enough for some of the technicaly minded here to work what it is that causes the problem, and prehaps what exactly it is that is needed to get around it.

Moppie, I read that link a while back. Yeah, it sure didn't give any details.

With londuck's help, I've been working on a possible solution for that Ebay Sonia optical slave. From my testing, I found that it's the Sonia slave actually holding a close circuit after it's optically triggered. Seems to me that optical slave depends on the flash's current/voltage to reset itself (open circuit again), which Canon EXs don't provide.

So my objective is to make that optical salve to reset after triggered, regardless of what flash it's connected to. After playing with different electronic components and various series/parallel connections, I came up with this: a resistor and a small LED in series on the hot side of the sync cable.

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Would you post a schedule of that, because I'm not sure I get it...
The led and 220 ohm(?) resisors are in series in the sync cable, so not parallel 'over' the sync? That would lower the sync current, right? Also, what direction is the led?

In the link by Moppie to the graphic-fusion, the simple mod to the internal wiring was to put a small jumper across the 3 internal diodes, thus bypassing the diodes. It is a pretty simple mod to do, and should work fine for most flashes.

I'll see if I can locate one of these units and try the mod for those interested.

Michael

I have video of Sonia slaves working perfectly with multiple EX flashes and the ST-E2:

https://photography-on-the.net …?t=297466&highl​ight=sonia

Where do you get the Sonia slaves? I just searched around, including eBay, and could not find them.

Does the Sigma 500 Super have the same issue as the Canon flashes?

rdsmith3 wrote in post #3076097
Where do you get the Sonia slaves? I just searched around, including eBay, and could not find them.

Does the Sigma 500 Super have the same issue as the Canon flashes?

Just type in "Sonia" and "slave" in the ebay search engine.

Without the quotes of course.

Enjoy! Lon

You type in "Sonia" in ebay's search and this comes up:

http://cgi.ebay.com …ZWDVWQQrdZ1QQcm​dZViewItem

Thanks. I just searched, and that one did not come up. Maybe I was just searching the titles. Or maybe it is operator error.

cosworth wrote in post #3076057
I have video of Sonia slaves working perfectly with multiple EX flashes and the ST-E2:

https://photography-on-the.net …?t=297466&highl​ight=sonia

Cosworth has been able to get his Sonia optical slave to function nicely with his Canon EX flash, but I have tried at least 5 different Sonia flash units with a Canon 550EX flash and they definitely would not work. I was using the standard range Sonia optical slaves, not the high range unit (there are two versions from Sonia that look a lot alike). Lotto was using the exact type of Sonia optical slaves that I was with a Canon 580EX and 430EX and they do not function properly.

Edit: I also tried a Hama optical slave and an older Wein optical slave (not the "new" Wein Peanut) and they functioned almost identical to the Sonia optical slaves I tested.

There is likely some physical difference between the optical slave that Cosworth has, and the ones that both Lotto and I have been working with, as the ones that Lotto and have definitely will not work with Canon EX flash units.

As a starting point, Cosworth do you know if your optical slave is the standard or extended range version?

Also, I would be very glad to send Cosworth one of the optical slaves that I have had difficulty with to see if it may work with his Canon EX flash.

Cosworth just contact me via private email so I can get you one of the Sonia optical slaves I have.

As an aside, I can get my Sonia optical slaves to work very nicely with numerious other flash units, both hotshoe mount and studio flash units (just not Canon EX units). They are nice, and inexpensive optical slaves.

As another aside, with the exception of the "new" Wein Peanut optical slave*, and a very expensive Metz optical slave, and the one Cosworth has, I am not aware of any optical slaves that function properly with a Canon EX flash unit.

*The "new" Wein Peanut has other issues that may not make it a reliable choice. See this thread.

http://www.flickr.com …iscuss/72157600​098851800/

Enjoy! Lon

rdsmith3 wrote in post #3076097
Does the Sigma 500 Super have the same issue as the Canon flashes?

No. The Sigma Super has a built-in optical slave. No clunky add-ons needed.

Lon-Did you try to bypass the diodes as Sarah Fox did in the the link referenced by Moppie, or did you only make the external resistor and LED patch? I have sent an e-mail to naive-buyer to verify that the mod by Sarah Fox was using his extended range version, or the standard version, prior to purchasing some of them for experimentation.

From the eBay ads, it appears I have the extended range version. My shoe is a bit different in that the inputs are dead center instead of offset.

jmb4370 wrote in post #3076418
Lon-Did you try to bypass the diodes as Sarah Fox did in the the link referenced by Moppie, or did you only make the external resistor and LED patch? I have sent an e-mail to naive-buyer to verify that the mod by Sarah Fox was using his extended range version, or the standard version, prior to purchasing some of them for experimentation.

Michael,

I just have the optical slaves, no hotshoe assemblies. These are Sonia optical slaves with a PC connector and they are the "standard" range version, not the extended range version.

So, I did not deal with any diode issues in hotshoe adapters. I just wired them to a Canon 550EX using jumpers, patch cords, and/or a garden variety hardwired hotshoe adapter.

I do not even own a Canon EX flash unit. But, about 5 or 6 months ago I borrowed a friend’s 550EX and experimented a bit with these optical slave. I only had the flash for about a week and within that week I only devoted a few hours to the project.

I found that if I put about a 6K resistor in series with these optical slaves, I could overcome the lockup issue with the Canon EX flash. But, I only confirmed gross function as I did not have enough time to determine if the 6K resistors gave efficient and "reasonable" function.

I also tried the same 6K resistor on a Hama and older Wein (not a “new” peanut) optical slaves (that when connected “bare” to a 550EX would lock it up after the first flash burst) that netted gross function very like the Sonia optical slaves.

I then returned the borrowed 550EX flash.

Lotto then started his far more in depth experimentation (he has two Canon EX flash units) and tried the 6K series resistor as a starting point. His more thorough investigation revealed that indeed the 6K resistor did provide gross function, but it would only work when the triggering flash burst was at a relatively low power (yes, it worked well at low powered triggering flash flash, but not at high powered triggering flash).

Lotto then tried other experiments and developed the approach with the diode as he explains above.

If I had a Canon EX flash, I would try this.

• A 1K resistor in series with the optical slave
  
• A capacitor of about 1 micro farad in parallel with this 1 K resistor, but it might take a capacitor much lower or higher that this “stab” experimental value.

I'll do a full on test with the two and take in-depth shots of both slaves to see the differences between the two.